Apparatus for treating galvanizing work



Feb. 23, 1943. D. EDGE EI'AL APPARATUS FOR TREATING GALVANIZING WORK Filed Se t, 12, 1939 opens.

Patented Feb. 23, 1943 APPARATUS FOR TREATING GALVANIZING WORK Dexter Edge and Perry H. Wray, Gary, Ind. Application September 12, 1939, Serial No. 294,550

3 Claims. (Cl. 9=1 12.1)

This invention relates to the heat treatment of galvanized steel work. Its principles are particularly applicable to the galvanizing of steel strip and sheets, but they may be applied to th treatment of other products.

A specificexample of the invention is illustrated by the accompanying drawing, in which:

Figure 1 is a vertical section, and

Figure 2 is a cross section from the line IIII in Figure 1.

More particularly, the drawing shows a galvanizing pot I through which steel sheets S are continuously passed by the entering rolls 2, middle rolls 3, and the exit rolls 4 of a galvanizing machine, the usual guides 5 serving to guide the sheets from one set of rolls to the other in the usual manner. ,1

The usual procedure is to permit'the sheets to cool directly in the air after they have left the pot, crystallization of the zinc producing the characteristic spangled surface.

In the case of the present invention, a continuous furnace B is mounted on a carriage I running on tracks 8, the arrangement being such that the furnace can be run upto theside of the pot I adjacent the exit rolls 4. This furnace has an entrance 9, an exit 10, and a chain conveyer ll running through the furnace so as to carry the sheets from the entrance, through the furnace, and out its exit.

Rod guides [2 rise from the galvanizing machine at the exit rolls 4 and curve into the furnace by Way of the entrance 9, these guides serving to deflect the sheets urged upwardly from the pot l by the exit rolls 4, into the entrance 9 of the furnace and onto thefurnace conveyer I l, the latter then carrying the sheets through the furnace.

As shown by the drawing, no part of the furnace is directly over the exit rolls 4 from which point the galvanizing pot gives off fumes as the sheets leave the zinc. The entrance 9 is well to one side of this point so that, although positioned above the galvanizing pot, it is not in line with the ascending fumes.

The exit I0 is provided with a depending gate or baflle I3, while the entrance 9 rises to the full .height of the inside of the furnace, such an entrance being necessary to provide room for entrance of the guides l2 when the furnace is run into position and providing an arrangement in conjunction with the gate or bafiie I3, wherein the entrance 9 opens from the furnace inside to a height greater than that with which the exit [0 This arrangement provides a means for creating a draft through the furnace from the exit 10 to the entrance 9, this drawing in the outside atmosphere in a flow counter to the moving direction of the sheets. A fume exhauster H is positioned to collect fumes exiting from the furnace, 6 by reason of the just mentioned draft, and

fumes rising from the pot l where the sheets are urged from the zinc by the exit rolls 4 of the galvanizing machine.

The furnace 6 is provided with a plurality of bafiles l5 which extend upwardly from the furnace bottom to adjacent the traveling path of the sheets, passages 5 being formed in these bafiles for the passage of the bottom loop of the chain conveyer l I. These bafiies divide the furnace into a plurality of heating zones, radiant heaters l1 being positioned between each of the baflles, and

above the traveling path of the sheets at locations approximately above the various zones. These heaters are illustrated as comprising tubes in which gas is burnt by means of burners l8, control of these burners permitting control of the temperatures of the various heating zones, or, if necessary in some instances, the elimination of one or. more of the heating zones so far as their heating effect is concerned. Other forms of radiant heaters may be used but they should provide sufficient flexibility to permit the application of various amounts of heat to the sheets, under controlled conditions.

Due to the position of the furnace 6, the sheets leaving the galvanizing pot I enter the furnace prior to their zinc coating spangling, and during their passage through the furnace they acquire a dull gray-white finish, this providing a product that is better adapted to some uses than the conventional spangling appearance. This finish is obtained by the oxidizing action of the atmosphere drawn through the furnace when the prop- -er temperature conditions are attained. Due to its flexibility, the furnace can apply the proper amount of heat to obtain these temperatures even though the gages of the sheets and the weight or thickness of their zinc coatings, may vary. Furthermore, adjustment of the thickness and character of the zinc and iron alloy layer bonding the zinc to the steel may be effected by controlling the heat applied to the galvanized sheets.

It is to be noted that the finish of the sheets is not spoiled by reason of the furnace drawing fumes from the galvanizing pot into its interior, the draft through the furnace preventing this trouble; The various bafiles l5 function to prevent. the sucking of fumes from the galvanizing pot into the furnace by way of the entrance 9 counter to the flow of the draft through the furgalvanizing machine on their way to the entrance,

8 of the furnace. This port, therefore, radiates heat directly to the sheets leaving the galvanizing pot so as to provide a further precaution against their undesirably cooling during the interval they are not receiving heat from either the galvanizing pot or the furnace 6. By means of this arrangement incipient spangling of the zinc on the sheets is positively prevented, although the closeness of the furnace to the pot is sufficient to assure the sheets reaching the furnace prior to spangling of the zinc coatings, in many instances.

It is to be understood that strip steel may be continuously galvanized in the same manner. In all cases, the work is continuously passed through the galvanizing pot by a suitable means and is then continuously passed through the furnace, the latter being heated by means other than open oxygen-consuming flames and being provided with regulated amounts of an oxidizing atmosphere, this providing the desired dull gray-white finish when the furnace is positioned sufliciently close to the galvanizing pot.

"We claim:

1. The combination of a galvanizing pot, means for guiding continuously traveling work through said pot, a continuous furnace having an entrance positioned to receive work leaving-said pot prior to its zinc coating spangling, an exit, said work continuously passing through said furnace by way of said entrance and exit, means for causing a draft through said furnace from said-exit to said entrance, said furnace having a plurality of radiant heaters and baffles arranged between said heaters to provide a plurality of heating zones in said furnace through which said work successively passes, said baffles extending upwardly from the furnace bottom to adjacent the traveling path of said work, and said means for creating a draft to its zinc coating spangling, an exit, said work continuously passing through said furnace by way of said entrance and exit, means for causing a draft through said furnace from said exit to said entrance, said furnace having a plurality of radiant heaters and baffles arranged between said heaters to provide a plurality of heating zones in said furnace through which said work successively passes, said bafiles extending upwardly from the furnace bottom to adjacent the traveling path of said work, and said means for creating a' draft having an opening with a radiant heater adjacent furnace bottom to adjacent the. traveling path ofthereto radiating heat to said work as it travels from said pot to said entrance.

3. The combination of a galvanizing pot, means for guiding continuously traveling work through said pot, a continuous furnace having an entrance positioned to receive work leaving saidpot prior to its zinc coating s'pangling, an exit, said work continuously passing through said furnace by way of said entrance and exit, means for causing a draft through said furnace from said exit to said entrance, said furnace having a plurality of radiant heaters and baffles arranged between said heaters to provide aplurality of heating zones in said furnace through which said work successively passes, said baflles extending upwardly from the said work, and said means for creating a draft being an arrangement wherein said entrance.

opens from the furnace insideto a height greater than said exit opens, whereby said baflles forming said heating zones function to prevent sucking of fumes from said pot into said furnace by way of said entrance counter to the flow of said draft, said entrance being positioned above and to the 1 side of said not so as to be out of the direct path being, an arrangement wherein said entrance opens from the furnace inside to a height greater than said exit opens, whereby said baffles forming said heating zones function to prevent sucking of fumes from said pot into said furnace by way of said entrance counter to the flow of said draft.

2. The combination of a galvanizing pot, means for guiding continuously traveling work through said pot, a continuous furnace having an entrance l positioned to receive work leaving said 'pot prior of fumes rising from said pot and said furnace having an opening with a radiant heater adjacent thereto radiating heat to said work as it travels from said pot to said entrance, a fume collector being arranged adjacent said entrance and the portion of said pot where said work leaves the same.

DEXTER EDGE. vPERRY H. WRAY. 

